A clean-sheet design. That's what you'll find in regards to Voltec in the next-generation 2016 Chevrolet Volt.

You'd think Chevrolet would carry over at least some parts from Voltec 1 to Voltec 2, right? It would seem to make sense to take the existing system and perfect it, but that's not what General Motors has done.

Instead, GM engineers started fresh. How fresh? Well, GM threw out every part found in Voltec 1 and created Voltec 2 in such a way that it shares only one part in common with the original Voltec system. That part, "a little yellow plastic intra-plant shipping cap" will not actually be found on the 2016 Volt, since it's used solely for intra-plant shipping purposes. So, in essence, Voltec 2 is then entirely new. Per Green Car Congress:

"The second-generation Volt, which makes its world debut in about 10 weeks at the North American International Auto Show in Detroit, features a clean-sheet, all-new Voltec propulsion system—new battery, new electric drive unit, new power electronics and new range-extending engine. At an introductory media briefing on the new powertrain held at the Warren Transmission Plant in Michigan, where the new drive unit will be built, Larry Nitz, GM Executive Director, Transmission and Electrification, noted that the only common part between the gen 1 and gen 2 drive units was for the manual selector."

Nitz adds:

"In a five-year period, I can’t think of any other product that we have that we have gone through a complete, a complete reengineering."

In fact, we can't think of any automobile that's been completely re engineered just five years after its debut.

Green Car Congress breaks down some specifics on the 2016 Volt as follows:

The battery cells, with a tweaked NMC/LMO chemistry from LG, increase storage capacity by 20% volumetrically when compared to the original cell.

Overall the engineering team increased efficiency and reduced weight; the drive unit is up to 12% more efficient in operation—although GM has yet to quantify publicly what that means in terms of range or fuel economy—and 100 lbs (45 kg) lighter. The battery system, with fewer, albeit larger, cells (192 vs. 288) is nearly 30 lbs (13.6 kg) lighter, but offers more capacity (also unspecified at this point) than its predecessor.